Area Forecast Discussion
Issued by NWS Grand Rapids, MI

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FXUS63 KGRR 141744
AFDGRR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND RAPIDS MI
144 PM EDT SUN SEP 14 2014

LATEST UPDATE...
AVIATION

.SYNOPSIS...
ISSUED AT 258 AM EDT SUN SEP 14 2014

A COLD FRONT WILL BRING SOME SHOWERS TONIGHT AND INTO MONDAY THEN
FAIR WEATHER WILL RETURN FOR TUESDAY AND THE REST OF THE WEEK.

&&

.UPDATE...
ISSUED AT 1112 AM EDT SUN SEP 14 2014

LOWERED MAX TEMPS SLIGHTLY AS THE LOW CLOUDS SHOULD HOLD OVER THE
CWA. THERE WILL BE A FEW PEEKS OF SUNSHINE...MORE SO TOWARD LATE
AFTERNOON/EARLY EVENING.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 258 AM EDT SUN SEP 14 2014

FORECAST ISSUE IN THE NEAR TERM IS TIMING OF SHOWERS TONIGHT
THROUGH MONDAY NIGHT. SFC HIGH MOVES EAST THIS AFTERNOON WITH
MODEST MOISTURE RETURN THIS EVENING. MODEL SOUNDINGS INDICATE IT
WILL TAKE UNTIL AFTER MIDNIGHT FOR SATURATION OF THE LOWER LEVELS
AND THEREFORE THE RAIN SHOULD HOLD OFF THIS EVENING. VORTICITY
MAX DIVING OVER THE WEST COAST RIDGE AMPLIFIES AN APPROACHING
SHORTWAVE TROUGH WITH UPPER DIFFLUENCE AHEAD OF THE TROUGH AXIS
HELPING TO ENHANCE THE SHOWERS LATE TONIGHT...WITH MOISTURE
TRANSPORT INTO LOWER MICHIGAN CONTINUING THROUGH EARLY MONDAY
AHEAD OF A SFC COLD FRONT.

EXPECT THE BULK OF THE RAIN TO FALL MONDAY AND THEN GRADUALLY END
FROM NORTHWEST TO SOUTHEAST MONDAY NIGHT AS THE SFC FRONT MOVES
THROUGH AND SFC RIDGING/HEIGHT RISES MOVE IN.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 258 AM EDT SUN SEP 14 2014

WE ARE STILL LOOKING AT A GENERALLY DRIER FCST FOR THE LONG TERM
COMPARED TO THE LAST COUPLE OF WEEKS. THE PERIOD FROM TUE NIGHT
THROUGH FRI LOOKS ALMOST ENTIRELY DRY. THE UPPER PATTERN WILL
FEATURE THAT ALL TOO FAMILIAR NW FLOW THAT HAS DOMINATED THE WEATHER
OVER THE REGION SINCE LAST WINTER. EVEN WITH THE NW FLOW IN
PLACE...THE UPPER JET WILL REMAIN NORTH OF THE AREA...KEEPING SHORT
WAVE TROUGHS OUT OF THE AREA AND SFC RIDGING NEARBY. A FRONT TRIES
TO SINK SOUTH INTO THE AREA ON THU FROM THE NE...HOWEVER WE FEEL
THAT THE UPPER AIR PATTERN SHOULD HOLD IT FROM MOVING TOO FAR INTO
THE AREA.

BETTER AGREEMENT HAS COME TOGETHER FOR THE NEXT ROUND OF PCPN
SOMETIME NEXT WEEKEND. JET ENERGY EXPECTED TO COME ONSHORE OVER THE
WEST COAST WILL EVENTUALLY HELP TO INDUCE LOW DEVELOPMENT ACROSS THE
NRN PLAINS AND UPPER MIDWEST. THIS LOW IS EXPECTED TO NOW LIFT INTO
CANADA BEFORE IT REACHES MI. THIS WILL KEEP THE PCPN N AND W OF THE
AREA A BIT LONGER UNTIL THE FRONT IS PUSHED INTO THE AREA LIKELY
DURING THE DAY ON SAT INTO SAT NIGHT. THIS WILL ALLOW FOR A BETTER
PUSH OF WARMER AIR AHEAD OF IT AND A MILD PERIOD OF WEATHER WITH
HIGHS LIKELY IN THE 70S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 144 PM EDT SUN SEP 14 2014

MADE VERY FEW CHANGES TO THE PREVIOUS TAFS. MORNING UPPER AIR SOUNDINGS
STRONGLY SUGGEST THAT A SCATTERED TO BROKEN LAYER OF CLOUDS WILL
PERSIST TODAY INTO THIS EVENING WITH BASES FAIRLY STEADY AROUND
5000 FT AGL. CONFIDENCE THEREFORE REMAINS FAIRLY HIGH FOR CONTINUED
VFR CONDITIONS. DID NOT CHANGE THE TIMING FOR RAIN SHOWERS COMMENCING
MONDAY MORNING. A GREATER COVERAGE OF PRECIPITATION IS EXPECTED
TOWARDS 18Z MONDAY.

&&

.MARINE...
ISSUED AT 258 AM EDT SUN SEP 14 2014

WINDS AND WAVES WILL BE INCREASING TODAY WITH SOME WAVES AROUND 4
FEET AROUND BIG AND LITTLE SABLE POINTS. WE MAY NEED A SMALL CRAFT
ADVISORY NORTH OF WHITEHALL FOR LATE THIS AFTERNOON OR EVENING.


&&

.HYDROLOGY...
ISSUED AT 258 AM EDT SUN SEP 14 2014

NO HYDRO ISSUES.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&

$$

UPDATE...JK
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...NJJ
AVIATION...TJT
HYDROLOGY...OSTUNO
MARINE...OSTUNO






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